Consent will be obtained from the patient before entering the study, if possible, or from the next of kin as soon as possible after starting vasopressor therapy. Indeed, in such cases, vasopressor therapy should anyway be started, either with dopamine or with norepinephrine, and these 2 therapies are currently equally valid 1st choices. As soon as possible, the next of kin will be informed and deferred consent obtained. If the patient recovers, and is able to consent, consent will then be obtained.